Variable-gain stages incorporated into the transmission chains of cellular mobile telephones are generally made up of amplifier cells comprising capacitive inductive resonant circuits (LC), and attenuator cells. In particular, such an architecture exhibits drawbacks with current consumption. Generally, the performance of such an architecture is optimized for maximum output power whereas most of the time the telephone operates at an intermediate power.
Moderate reductions in current may be obtained by supplementing with additional circuitry at the level of the biasing of the transistors of these cells. As a result, this further complicates the architecture and deforms the power supervision function, i.e., output power being dependent on the control voltage.